badpage: simplify page_alloc flag check+clear (79f4b7bf) · Commits · 戴 / test

include/linux/page-flags.h

+8 −17

Original line number	Original line	Diff line number	Diff line
	@@ -373,31 +373,22 @@ static inline void __ClearPageTail(struct page *page)
	#define __PG_MLOCKED 0		#define __PG_MLOCKED 0
	#endif		#endif

	#define PAGE_FLAGS (1 << PG_lru \| 1 << PG_private \| 1 << PG_locked \| \
	1 << PG_buddy \| 1 << PG_writeback \| \
	1 << PG_slab \| 1 << PG_swapcache \| 1 << PG_active \| \
	__PG_UNEVICTABLE \| __PG_MLOCKED)

	/*
	* Flags checked in bad_page(). Pages on the free list should not have
	* these flags set. It they are, there is a problem.
	*/
	#define PAGE_FLAGS_CLEAR_WHEN_BAD (PAGE_FLAGS \| \
	1 << PG_reclaim \| 1 << PG_dirty \| 1 << PG_swapbacked)

	/*		/*
	* Flags checked when a page is freed. Pages being freed should not have		* Flags checked when a page is freed. Pages being freed should not have
	* these flags set. It they are, there is a problem.		* these flags set. It they are, there is a problem.
	*/		*/
	#define PAGE_FLAGS_CHECK_AT_FREE (PAGE_FLAGS \| 1 << PG_reserved)		#define PAGE_FLAGS_CHECK_AT_FREE \
			(1 << PG_lru \| 1 << PG_private \| 1 << PG_locked \| \
			1 << PG_buddy \| 1 << PG_writeback \| 1 << PG_reserved \| \
			1 << PG_slab \| 1 << PG_swapcache \| 1 << PG_active \| \
			__PG_UNEVICTABLE \| __PG_MLOCKED)

	/*		/*
	* Flags checked when a page is prepped for return by the page allocator.		* Flags checked when a page is prepped for return by the page allocator.
	* Pages being prepped should not have these flags set. It they are, there		* Pages being prepped should not have any flags set. It they are set,
	* is a problem.		* there has been a kernel bug or struct page corruption.
	*/		*/
	#define PAGE_FLAGS_CHECK_AT_PREP (PAGE_FLAGS \| \		#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
	1 << PG_reserved \| 1 << PG_dirty \| 1 << PG_swapbacked)

	#endif /* !__GENERATING_BOUNDS_H */		#endif /* !__GENERATING_BOUNDS_H */
	#endif /* PAGE_FLAGS_H */		#endif /* PAGE_FLAGS_H */

mm/page_alloc.c

+6 −13

Original line number	Original line	Diff line number	Diff line
	@@ -231,7 +231,6 @@ static void bad_page(struct page *page)
	printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"		printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
	KERN_EMERG "Backtrace:\n");		KERN_EMERG "Backtrace:\n");
	dump_stack();		dump_stack();
	page->flags &= ~PAGE_FLAGS_CLEAR_WHEN_BAD;
	set_page_count(page, 0);		set_page_count(page, 0);
	reset_page_mapcount(page);		reset_page_mapcount(page);
	page->mapping = NULL;		page->mapping = NULL;
	@@ -468,16 +467,16 @@ static inline int free_pages_check(struct page *page)
	(page_count(page) != 0) \|		(page_count(page) != 0) \|
	(page->flags & PAGE_FLAGS_CHECK_AT_FREE)))		(page->flags & PAGE_FLAGS_CHECK_AT_FREE)))
	bad_page(page);		bad_page(page);
	if (PageDirty(page))
	__ClearPageDirty(page);
	if (PageSwapBacked(page))
	__ClearPageSwapBacked(page);
	/*		/*
	* For now, we report if PG_reserved was found set, but do not		* For now, we report if PG_reserved was found set, but do not
	* clear it, and do not free the page. But we shall soon need		* clear it, and do not free the page. But we shall soon need
	* to do more, for when the ZERO_PAGE count wraps negative.		* to do more, for when the ZERO_PAGE count wraps negative.
	*/		*/
	return PageReserved(page);		if (PageReserved(page))
			return 1;
			if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
			page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
			return 0;
	}		}

	/*		/*
	@@ -621,13 +620,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
	if (PageReserved(page))		if (PageReserved(page))
	return 1;		return 1;

	page->flags &= ~(1 << PG_uptodate \| 1 << PG_error \| 1 << PG_reclaim \|		page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
	1 << PG_referenced \| 1 << PG_arch_1 \|
	1 << PG_owner_priv_1 \| 1 << PG_mappedtodisk
	#ifdef CONFIG_UNEVICTABLE_LRU
	\| 1 << PG_mlocked
	#endif
	);
	set_page_private(page, 0);		set_page_private(page, 0);
	set_page_refcounted(page);		set_page_refcounted(page);

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